SGAL project

The Scene Graph Algorithms Library (SGAL) is a toolkit that supports theconstruction and maintenance of directed acyclic graphs that representscenes and models in three-dimensional space. The toolkit consists oftwo libraries, namely SGAL and SCGAL, and an application, called player,which enables users to visualize the scene in an interactive manner. Theplayer parses input files that describe the scene in a degenerate yetextended VRML format. The format is degenerate, as not all VRML featuresare supported (yet). However, it has been extended to support severalnew features. For example, it has been extended with several geometrynode types, such as the Assembly node type, which represents assembliesor subassemblies; the AssemblyPart node type, which represents parts ofassemblies; the SphericalGaussianMap node type, which represents(spherical) Gaussian maps of convex polytopes in 3D, and theArrangementOnSphere, which represents arrangements of geodesic arcsembedded on the sphere. The extended format also supports, for example, anode type called ExactCoordinate, which represents exact coordinates, andenables the provision of exact rational coordinates as input. Each nodeobject of the three types AssemblyPart, SphericalGaussianMap, andArrangementOnSphere internally maintains the CGAL data structure thatrepresents an arrangement of geodesic arcs embedded on the sphere.